# US 12,016,127 B2 · Liquid metal infiltration rework of electronic assembly > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,016,127 B2 - Document ID: US12016127B2 - Status: Granted - Kind: B2 - Application number: 18/354,957 - Filed: 2023-07-19 - Published: 2023-11-16 - Granted: 2024-06-18 - Earliest claimed: 2019-10-22 - Assignees: International Business Machines Corporation - Applicants: International Business Machines Corporation - Inventors: Mark K. Hoffmeyer; Timothy P. Younger - Web page: https://patentgrep.com/patent/US12016127B2 ## CPC - H05K 13/0486: {Replacement and removal of components} - B23K 1/0016: {Soldering of electronic components} - B23K 1/018: Unsoldering; Removal of melted solder or other residues - H05K 2203/043: Reflowing of solder coated conductors, not during connection of components, e.g. reflowing solder paste - H05K: PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS - B23K: SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM ## Abstract Provided is a method for removing an electronic component from a printed wiring board. The method comprises applying an embrittlement agent to a lead of an electronic component that is soldered to the printed wiring board. The electronic component is removed from the printed wiring board by breaking the embrittled lead. ## Claims ### Claim 1 A system comprising: a memory; and a processor communicatively coupled to the memory, wherein the processor is configured to perform a method comprising: applying an embrittlement agent to a soldered joint of an electronic component that is soldered to a printed wiring board; and removing the electronic component from the printed wiring board by breaking the embrittled joint. ### Claim 2 (depends on 1) The system of claim 1, wherein the embrittlement agent is a paste comprising metal that causes liquid metal embrittlement when it infiltrates the joint of the electronic component. ### Claim 3 (depends on 1) The system of claim 1, wherein the method further comprises: heating the applied embrittlement agent to a temperature that meets or exceeds a reflow temperature of the embrittlement agent; and holding the embrittlement agent at the temperature for an amount of time to allow the embrittlement agent to at least partially diffuse into the joint, wherein removing the electronic component from the printed wiring board is performed after the embrittlement agent has at least partially diffused into the joint. ### Claim 4 (depends on 3) The system of claim 3, wherein the amount of time and the temperature are based on the composition of the embrittlement agent. ### Claim 5 (depends on 1) The system of claim 1, wherein removing the electronic component from the printed wiring board comprises applying a mechanical force to break the joint of the electronic component. ### Claim 6 (depends on 1) The system of claim 1, the method further comprising: removing, after removing the electronic component, residual alloyed solder from the printed wiring board using a vacuum solder tool; depositing fresh solder paste on pads on the printed wiring board; placing a new electronic component on the printed wiring board in place of the electronic component; and attaching the new electronic component using a reflow soldering process. ### Claim 7 (depends on 1) The system of claim 1, wherein the embrittlement agent comprises a flux carrier and metal particles. ### Claim 8 (depends on 7) The system of claim 7, wherein the metal particles include one or more particles selected from the group consisting of elemental copper, a copper alloy, elemental silver, a silver alloy, elemental antimony, and an antimony alloy. ### Claim 9 (depends on 7) The system of claim 7, wherein the metal particles further comprise one or more particles selected from the group consisting of elemental gallium, a gallium-tin alloy, a gallium-indium alloy, and a gallium-tin-indium alloy. ### Claim 10 (depends on 1) The system of claim 1, wherein the embrittlement agent further comprises an alcohol emulsion carrier. ### Claim 11 (depends on 1) The system of claim 1, wherein the embrittlement agent comprises: a first set of metal particles that cause liquid metal embrittlement when deposited on a metal component; and a second set of metal particles, wherein the second set of metal particles includes one or more metal particles selected from the group consisting of elemental copper, a copper alloy, elemental silver, a silver alloy, elemental antimony, and an antimony alloy. ### Claim 12 (depends on 11) The system of claim 11, wherein the first set of metal particles include one or more metal particles selected from the group consisting of elemental gallium, a gallium-tin alloy, a gallium-indium alloy, and a gallium-tin-indium alloy. ### Claim 13 (depends on 1) The system of claim 1, wherein the embrittlement agent is a preformed sheet. ### Claim 14 (depends on 13) The system of claim 13, wherein applying the embrittlement agent to the soldered joint comprises: placing the preformed sheet over the electronic component; heating the preformed sheet to a temperature that meets or exceeds a reflow temperature of the embrittlement agent; and holding the embrittlement agent at the temperature for an amount of time to allow the embrittlement agent to at least partially diffuse into the soldered joint. ### Claim 15 A system comprising: a memory; and a processor communicatively coupled to the memory, wherein the processor is configured to perform a method comprising: applying an embrittlement agent to a soldered joint of an electronic component that is soldered to a printed wiring board; heating the applied embrittlement agent to a temperature that meets or exceeds a reflow temperature of the embrittlement agent; holding the embrittlement agent at the temperature for an amount of time to allow the embrittlement agent to at least partially diffuse into the joint; and removing, after the embrittlement agent has at least partially diffused into the joint, the electronic component from the printed wiring board by breaking the embrittled joint, wherein the embrittlement agent comprises metal particles, wherein the metal particles include one or more particles selected from the group consisting of elemental copper, a copper alloy, elemental silver, a silver alloy, elemental antimony, and an antimony alloy. ### Claim 16 (depends on 15) The system of claim 15, wherein the embrittlement agent is a paste comprising metal that causes liquid metal embrittlement when it infiltrates the joint of the electronic component. ### Claim 17 (depends on 15) The system of claim 15, wherein the amount of time and the temperature are based on the composition of the embrittlement agent. ### Claim 18 (depends on 15) The system of claim 15, wherein removing the electronic component from the printed wiring board comprises applying a mechanical force to break the joint of the electronic component. ### Claim 19 (depends on 15) The system of claim 15, wherein the method further comprises: removing, after removing the electronic component, residual alloyed solder from the printed wiring board using a vacuum solder tool; depositing fresh solder paste on pads on the printed wiring board; placing a new electronic component on the printed wiring board in place of the electronic component; and attaching the new electronic component using a reflow soldering process. ### Claim 20 (depends on 15) The system of claim 15, wherein: the embrittlement agent is a preformed sheet; and applying the embrittlement agent to the soldered joint comprises placing the preformed sheet over the electronic component.